Doctor knife maintaining mechanism for printing presses



A. WEISS Nav. 10, 1936.

DOCTOR KNIFE MAINTAINING MECHANISM FOR PRINTING PRESSES Filed Aug. 18, 1934 4 Sheets-Sheet l c INVENTOR:

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DOCTOR KNIFE MAINTAINING MECHANISM FOR PRINTING PRESSES n 4 Sheets-Sheet 2 Filed Aug. 18, 1934 Nov. 10, 1936. A WEISS 2,060,600

DOCTOR KNIFE MAINTAINING MECHANISM FOR PRINTING PRESSES I Filed Aug. 18, 1934 4 SheeS-Sheejl'l 3 M mvEN-rpn: 171g 1 105 Wil/@15,53

Nov. l0, 1936. Al WE|55 2,060,600

DOCTOR KNIFE MAINTAINING MECHANISM FOR PRINTING PRESSES Filed Aug. 18, 1934 4 Sheets-Sheet 4 lll/5' ATT ORNYS Patented Nov. 10, 1936 -oFFlcE DOCTOR KNIFE MAINTAINING MECHANISM FOR PRINTING PRESSES Adolph Weiss, Brooklyn, N. Y. Application August 18, 1934, Serial No. 740,365

22 Claims.

The present invention relates to a device for the completemaintenance of doctor knives such as are now in common use on rotary intaglio printing presses, for the wiping of the printing surface of intaglio printing cylinders.

Such doctor knives during their use in the printing press are in contact on their wiping edges with the printing surface of the cylinder and serve to remove the ysurplus ink from this surface leaving ink only inthe engravings which lie below said printing surface. The wiping action of the doctor cleans the unengraved portions of this surface in such manner that no discoloring will be noted on the printed material in the locations where said material has come in contact with these unengraved portions. However, due to the uneven wear, which is principally caused by the difference in the supporting surface on the cylinder for the doctorlknife at its wipingV edge due to the difference in the character and size of the engravings, the tendency of the wiping edge will be to lose its original efliciency and cause a ne film of ink to be left on the unengraved portions of said surface in various spots. When this condition arisesit will be necessary to restore or to recondition the wiping edge to its original efliciency.

For such purpose the devices in current use resort to grinding mechanism or to hand ling, but none of these means have been found quite adequate for several reasons. Where grinding means are used, the tendency of the doctor knife is to become distorted longitudinally at its wiping edge and to become wavy. This is due to the severe change in temperature caused by the high friction exerted by the grinding wheel upon the doctor and will become aggravated as the relative thickness of said doctor knife diminishes.

AIn some instances cooling fluids are applied to the doctor during the grinding pperation, but even this does not completely prevent distortion.

Moreover a Worn doctor knife presents a very uneven line at the wiping edge and differences as much as 1/8" in height may be observed between the highest and lowest points of said line.

LIf an attempt were made to remove these differences by grinding or filing with a single cut the amount of heat generated in removing the highest portions would hopelessly distort the doctor. 50 Consequently it is necessary to proceed with great caution and considerable skill to gradually level down these differences with several cuts until a straight line has been created. This method is therefore evidently very lengthy and 55 hazardous. The device shown in this invention.

overcomes such difliculties and provides a simple device'capable of efliciently removing the wom edge with a single cut, without a change in the temperature of the wiping edge to any extent, thus preventing any longitudinal distortion thereof. It 5 furthermore requires very little skill. to .operate and is inherently foolproof to permit an unskilled operator to produce a doctor knife of such high quality as to rival the product of a highly skilled operator usingcurrent methods and devices. f

Due to the uncertainty of the final results produced by current methods and devices as to the evenness of the wiping edge, it was necessary to provide various adjusting means on the printing .15 press to compensate for the differences caused' by such uneveness between the wiping edge andthe printing surface. Consequently every change of doctor knife necessitated `a readjustment of the wiping mechanism to bring the wip- 20 ing edge into 'alignment with the printing surface, thereby causing considerable delay in resuming printing operation. The wipingedge produced by the device and method herein described and illustratedpermits the maintenance lof a permanent alignment between the wiping edge-and the printing surface and consequently the readjustment of such alignment becomes unnecessary. In fact through the use of such device and method it becomes possible to operate a printing press where the means for adjusting such an alignment are completely eliminated, at the same time obtaining and maintaining an eiective and clean wipe on the printing surface.

When the doctor knife and its holderv are removed from -the printing press for the restoration of the wiping edge, they have accumulations of ink thereon. These must be removed manually or otherwise previous to suclrrestoration. 4;0 The devices in current use are either very inefficient or very elaborate and constitute an,in dependent device not combined with other operations. In my invention, the mechanism used for this operation is very inexpensive, "efficient and simple, it also skilfully combines such mechanism with the supporting structure of the mechanism performing other operations. f'The result is asavingin cost, space .and operating cost. ,50

The life of a doctor knife in constant use is rather short since a large portion has to be wasted. Consequently a reserve stock of the raw material is usually kept in store. Furthermore it is quite important that the length of the doctor'55 is customary to have a duplicate set of doctors and holders andhold them in readiness with the wiping edge restored when the doctors are being changed. In my invention the frame work of the machine is utilized to serve as a storage rack for the duplicate set and thereby save the cost and the space for such storage rack.

It will be noted, that this machine combines within a single structure practically all elements required for the maintenance of the wiping edge of doctor knives. These elements not4 only function normally but coact in numerous ways to serve a plurality of purposes.

In order that a. doctor may be conditioned effectively, the present invention has been designed and an object thereof is to provide a mechanism by means of which a doctor may be accurately set or positioned in a holder and subsequently trimmed or cut to cause the edge thereof to be parallel to the holder and to be properly positioned with respect thereto.

A further object of the invention is to provide a device by means of which a doctor may be completely reconditioned after having been removed from' a press, means being provided for removing ink therefrom and cleaning the same preparatory to setting and trimming the edge thereof.

A further object of the invention is to provide a doctor conditioning mechanism wherein the doctor may be vensioned prior to adjusting the same in the holder, the mechanism enabling the trimming or cutting of the doctor to be effected subsequently and without disturbing the adjusted position of the doctor in the holder.

A further object of the invention is to provide an improved cutting mechanism by means of which an edge of the doctor may be accurately and effectively trimmed or cut.

A further object of the invention is to provide a doctor conditioningmechanism wherein means is provided for flexing the doctor into a trimming or cutting position in order that the cutting operation may be effected more accurately.

Further objects, not specically enumerated above, will be apparent as the invention is described in greater detail in connection with the accompanying drawings, wherein:

Figure 1 is a view int` front elevation showing a vdoctor conditioning mechanism constructed in accordance with the present invention.

Figure 2 is a plan view of the device shown in Figure 1.

Figure 3 is a view in end elevation, taken from the left as viewed in Figure 1.

Figure 4 is a partial view in section, taken on the line 4 4 of Figure 1, and looking in the direction of the arrows.

Figure 5 is a partial View in section, taken on line 5 5 of Figure 4, and looking in the direction of the arrows.

Figure 6 is a detail plan view showing a doctor and doctor holder.

Figure '1 is a View in section, taken on line 1 1 of Figure 6, and looking in the direction of the arrows.

Figure 8 is a partial view in section, taken on line 8 8 of Figure 2, and looking in the direction of the arrows. This view showing the cutting mechanism as well as the doctor holder frame and the means for positioning and tensioning the doctor in the holder.

Figure 9 is a partial view in section taken on line 9 9 of Figure 8, and looking in the directionv of th arrows.

Figure 10 is a detail view showing the cutter drive and adjusting mechanism.

Figure 11 is a view in section, taken on line I I of Figure`9, and looking in the direction of the arrows.

Figure 12 is a view in section, taken on line |2 |2 of Figure 9, and looking in the direction of the arrows.

Figure 13 is an enlarged view showing the relation between the blades of the cutting mechanism. I

Figure 14 is a view in section, taken on line |4 |4 of Figures 8 and 15, and looking in the direction of the arrows.

Figure 15 is a partial plan view showing the doctor tensioning and setting mechanism above referred to.

Referring to the above drawings,I the mechanism in which the present invention is embodied is shown as being formed of a bed plate 20 which is supported upon end standards 2| and 22. The end standards are formed with opposed and correspondingly spaced ledges 22 upon which shelves 23 rest to provide storage spaces for doctors.

Between the end standards 2| and 22 a doctor cleaning mechanism is provided to remove ink and sediment from the doctor and holder as it comes from the printing press. This cleaning mechanism is formed as a cylindrical receptacle 24 (Figures l, 4, and 5). The receptacle is mounted in end sleeves 25 which are formed with cylindrical anges 26 Within which the ends of the receptacle 24 are received in such fashion as to form a liquid seal therebetween. The end heads 25 are furtherformed with annular shoulders 21 which are received within an annular recess formed by an annular flange 28 on the respective end standards 2| and 22. Three tie rods 29, 30, and 3| are shown as tying the receptacle and end heads to the anges 28 of the end standards, thus forming the receptacle as an integral part of the doctor conditioning mechanism.

Axially of the receptacle 24 a. shaft 32 extends, being journaled in the end heads by means of bearings 33. Packing glands 34 are received within cylindrical bearings 35, formed'in the end heads in order that an eiective uid seal may be maintained at the bearings for the shaft 32. One end of the shaft 32 `extends through the end head carried by the standard 2| and is driven by a motor 36 through a suitable transmission 31. 'Ihe motor and transmission may be mounted upon the standard 2| by means of a bracket 38 in a convenient manner.

Upon the shaft 32 and at spaced points, are

mounted collars 38, the collars being secured to the shaft 32 by means of set screws 39. These collars are formed with a plurality of L-shaped arms 40, in the ends of which set screws 4| are received. The arms thus form a plurality of` aligned recesses 42 in which the doctor and doctor holder may be secured prior to the cleaning thereof.

A typical doctor and doctor holder assembly is shown in Figures 6 and 7 wherein the holder is formed of plates 43 and 44 which are secured by means of set screws 45. The plate 44 is preferably recessed at 46 to receive a reinforcing Vblade 41 and the doctor 48 is secured between -the reinforcing blade 41 and one of the plates of the holder, being securely clamped in such position by means of the screws 45. This assembly,

when removed from a press, is inserted in one4 direction of rotation avoids the violent scooping of solvent within the tank and causes the doctor and holder to be repeatedly immersed in the solvent within the tank in order that cleaning thereof may be'effected. To avoid rapid evaporation of the solvent and splashing thereof from the tank, the tank is formed with a segmental cylindrically shaped lid 49 (Figures 2 'and 4) which may be .hinged upon the tie rod 30. The lid is formed with a sealing flange 50 which prevents loss of the solvent through the hinge joint and the other end of the lid is formed with a notched portion 5I in order that it may clip over the rod 3| and hold the same yieldingly in closed l position.-

In the event that a new doctor isto be prepared, a magazine 52 (Figures 1, 2, and 3) is provided. This magazine is secured to one of the end standards (here shown as being secured to end standard 2|) and is adapted to receive a coil of springsteel from which the doctor may be made. This coil is indicated in dot and dash lines at 53 in Figure 1, and as'shown therein, the outer end of the coil is extended through an outlet 54 in order that a length of the material may be drawn therethrough and placed upon a table 55 (Figures 1, 2, 3, and 8). This table is formed on the bed 20 and carries a clamp 56 slidably thereon. A set screw 51 and cooperating dowels enable the clamp to be secured to any desired position along the' length of the table 55. The clamp 56 is provided with a stop shoulder 56 and a, ange 58 is formed on the clamp 56 carrying a set screw 59, the flange 56 being spaced from the table 55. In this fashion, the material is drawn through the outlet 54 of the magazine 52 and placed in abutting relationship 'with respect to the stop 56. Screw 59 is then tightened and the free endV of the material is thus secured in the desired position. i

The magazine 52 is formed' with a stationary cutting edge 60,'over when drawn from the outlet 54 and a movable cutting member 6|, mounted upon an arm 62 which is hinged at 63, cooperates with the stationary cutting edge thereon when the arm 62 is actuated manually. Aspring 64 (Figure 3) is connected to an arm 6,5 which is formed on the lever 62, to urge the movable cutting member into the position shown in Figure 3.

Upon the bed 20, a table 66 is formed (Figures 3 and 8). Above the table 66 a. shaft 61 is journaled by means of brackets 68 (Figure 3). shaft is provided with a manually operated lever 69 in order that the shaft may be rocked into a plurality of positions. A flange 10 is formed on one of the brackets 68 (Flguresl, 8 and 14) and a spring-pressed pin 1I, carried by the lever 69 is adapted to engage recesses 12, 13 and 14 lwhich are formed in the 'flange 10.

The shaft 61 is provided with a plurality of collars 15 which are formed with arms 16 and 11 to receive the doctor holder assembly shown in Figures 6 and '7. Set screws 18 serve to clamp the holder assembly between the arms 16 and 11 which is clamped which the material liesl to cut the material lying and thus the assembly may be rocked into a plurality of positions as shown in Figure 8.

In introducing a holder assembly into the arms 16 and 11, the shaft 61 is turned to the position shown in solid lines in Figure 8 in which position the holder assembly is lowered into the recesses formed by the arms. The pin v1| is then released andthe lever 69 and shaft 61 rocked intg theright hand position shown in dot and dash lines in Figure 8: In this position, the doctor and reinforcing blade lie upon a table 19 which is supported in spaced relation to the table 66 by means of brackets 80 (Figures 1 and 2). At either end of the table 19 means is provided for clamping the doctor and applying longitudinal tension thereto. This means is shown in plan view in Figure A2 and in detail in Figures 8, 14 and 15.

Upon the bed 20, brackets 8| .are provided. These brackets are formed with grooves 82, extending transversely of they axis of shaft 61. Thel grooves are formed with undercut extensions 83 and receive plates 84 slidably therein. The plates 84 are formed with flanges 85 which are adapted to engage in the undercut portion 83 of the grooves 82 and thus the plates 84 are secured effectively in the brackets 8| with provision .for sliding motion in the grooves.l The plates 84 are formed with grooves 86 which receive flanges 81 formed upon threaded shafts 88 which are adapted to be screwed in and out of the brackets 8| by means of knurled knobs 89. In this fashion,A the transverse position of the plates 84 with respect to the table 19 is adjusted. v

Upon one of the plates 84, a groove 94 is formed in a direction transverse of the plates 88 (that is, parallel to the axis of shaft 61): 'Ihe groove 98 receives the plate 95 slidably, the plate 95 being formed with a slot 96 within which a collar corresponding bracket 8| and is manipulated by means of a knurled knob 99 to move the plate 95 longitudinally of the table 19. The plate 95 is provided with a separate clamping plate |00 thereto by means of a bolt |0| which' is formed on a pin |02 which engages the plate 95. 'I'he clamping plate |00 is adapted to be clamped down upon the adjacent end of the doctor which projects beyond the holder and reinforcing plate, asshown in Figure 6, when the doctor 'is moved into the position shown to the right in dot and dash lines in Figure 8. After loosening the set screws 45 in the holder, the ends of the doctor are clamped by manipulating the rbolts |0|. The position of the doctor with respectv to the holder is then properly gauged to position the' doctor properly between the clamping surfaces of the holder. Tension is applied to the doctor by backing off the plate 95 and its corresponding clamp |00. 'I'his tension tends to rigidify the doctor blade in such manner that it will tend to respond with its whole body instead of locally only to the adjustment to be made to establish the distance of projection of the doctor knife from its holder. This adjustment is accomplished-by means of the knurled knobs 89 which cause by means of their corresponding shoulders 81 the plates 84 to move with their correspondingclamps |90 transversely to the shaft 61. The object of this adjustment is t'o provide the worn edge of the doctor `|18 to be sufciently projected vfrom its holder 44 as to afford the said worn wiping edge to be completely removed during the trimming operation to be next described. After the doctor has been properly adjusted the set screws 45 are again tightened. In this connection, it is to be noted that provision for longitudinally tensioning the doctor is made at only one of the clamping plates although each clamping plate |00 is transversely adjusted with respect to the axis of the shaft 61. n

After the doctor has been set, tensioned, and clamped in the holder, the shaft 61 is rocked in a counterclockwise direction (as viewed in Figure 8) into the left hand position thereof as shown in dot and dash lines in Figure 8. In this position, the pin 1| engagesaperture 14 and the doctor engages the table 66 in such fashion as to be flexed upwardly thereby. In such flexedI position the doctor is ready to be trimmed or cut and this operation is effected by the cutting mechanism shown in Figures 8; 9,`f 10, 11, 12, and 13.

As showriin Figures 8 through 3, the cutting mechanism is mounted upon a carriage |03 which lis formed with a bracket |04 having dove-tailed portions |05. These dove-tailed portions are slidably received in cooperating dove-tailed grooves |06 which are formed in the underside of the bed 20 and thus permit the carriage |03 to be slid along the side of the table 66. 'I'he carriage|03 may be provided with supporting collars |01 which are' adapted to roll over a. supporting track |08 carried by the frame of the machine, thus relieving the dovetailed supporting members from the strain of the overhanging mechanism.

A shaft |09 Figure 12) is journaled in they carriage |03 and has secured to the ends thereof pinions l I0 and The pinion ||0 is adapted `to engage a gear rack I|2 which is secured to the bed 20 between the dove-tail grooves |06. Pinion engages a gear ||3 on the shaft ||4 to which a manually operated crank is secured. 'Ihe shaft 4 is journaled in the carriage |03 and, in this fashion, rotation of the crank ||5 causes the pinion ||0 to advance along the rack ||2 and thus move the carriage |03 longitudinally of the table 66.

Journaled in the carriage |03 is a shaft ||6 upon which a hub |1 is secured. A pinion ||8 is also secured to the shaft IIB and engages the gear ||3. A cutter disc ||9 is secured to the hub ||1 and is thus rotated as the carriage is advanced along the table 66. A lever |20 is pivoted upon an axis |2| and the end of the lever is adapted to be adjustably secured to the carriage |03 by means of the nut and bolt lock` ing mechanism |22. This mechanism is slidably received withina slot |23 formed in the carriage 03 in order that the position of the lever |20 may be conveniently adjusted. lever |20 is formed with an extension |24 upon which a shaft |25 is journaled. Shaft |25 is formed with a hub |26 and, at the other end thereof has a gear |21 secured thereto. A cutting disc |28 is secured to the hub |26 and gear |21 engages a gear |29 which is journaled upon the axis |2| and also engages the gear H3. In this fashion, gears ||8 and |21 rotate in opposite directions,

the speed of rotation thereof being the same by forming gears ||8 and |21 with an equal number of teeth on each.

The gear ratios between the rack ||2 and pinion H0 and between the gear H3 and pinion I bear such relation to the gear ratios between the gear H3 and the pinions |18 and |21 that the peripheral speeds of the cutter discs ||9 and |28 equal the longitudinal speed of travel of the carriage |03 along the table 66. The reason for mounting the cutter blade or disc |28 adjustably upon the carriage |03 is to provide for the securing of a desired overlap between the cutter blades and also for enabling the cutting point which is the intersecting point between the cutting edges of the two discs to be adjusted in order that it may be positioned directly over the axis of the shaft ||6. This is illustrated in Figure 13 wherein the cutting point is shown at |29, and the radius thereof on the axis of shaft H6 is shown by the dot and dash lines |30. The overlap between the blades ||9 and |28 is illustrated in Figure 13 and includes that portion of the blades lying between the radius line |30 and a radius line 3|.

A summary of the operation of the mechanism will show that the device includes a convenient and effective means for cleaning the doctor, pressure blade, and holder, this mechanism including the solvent tank 24 from which the solvent may be drained through a fitting 24. The doctor assembly after being secured in the rotating arms 40, is dipped into the solvent a sucient number of times to remove the sediment and ink therefrom.. This prevents the sticking of the doctor and pressure blade and enables the mechanism to be accurately and easily adjusted. This cleansing operation takesplace without scooping and violent agitation of the solvent.

The doctor assembly is then inserted in the rocking holder in a vertical position therein and the holder is rocked through 90 in order that the doctor and pressure blades may lie upon the table 19. In such position the set screws 45 are loosened and the overhanging ends of the doctor are clamped under the clamping plates |00. The clamping plates are then adjusted transversely of the axis of the shaft 61 by means of the knurled nuts 89 and after the doctor is properly positioned .with respect to the holder, the knurled nut 99 is turned to set up a desired tension in the doctor. After this is accomplished and the edge of the doctor is accurately gauged and parallel with the edge of the holder, the set screws 45 are tightened and the rock shaft 61 swung to the left in the position indicated in dot and dash lines in Figure 8.

As above noted, in the under. position of the doctor assembly, the doctor and reinforcing blade engage the table 66 and are flexed upwardly thereby. This produces a curvedV profile of the doctor and the reinforcing blade causing a longitudinal cross tension upon both tending to rigidify the flexed portion of said blades resting upon the table 66. It also tends to remove any wavy condition that may exist in the longitudinal edge of the doctor knife. 'I'he wiping edge of the doctor knife to be trimmed will be found in this position to lie in a horizontal plane even with the line corresponding with the meshing point of the cutter discs |28 and ||9, so that in this position the cutter discs will engage the doctor knife without any lifting or depressing action thus not disturbing the natural position of the overhanging edge. 'I'he carriage |03 which has previously been moved to one end of the table is then advanced along the table 66 by means of the manual lever ||5. Inasmuch as the travel of the carriage along the table 66 equals the peripheral speed of the rotor blades ||9 and 28 the cutting of the edge of the doctor takes place Without any tearing action thereon and in this fashion, a clean and accurate cut results. While the holder and doctor are in portion of the doctor be heated to a greater degree than other portions thereof. Under the old methods of reconditioning the edges of doctors,n the high points of the edges receive more grinding than the low points and thus great heat is created at the high points. This materially affects the temper ofl the edge of the doctor at these points.

and impairs the serviceability of the doctor. In accordance with the present invention all portions of the edge of the doctor are treatedalike and the temperatures thereof are uniform thus avoiding uneven heating along the length of the doctor andthe deleterious effects thereof.

' It will be noted that the fulcrum shaft 61 is in a parallel plane with the guideways |06 of the carriage carrying the trimming knives |28 and H9 and that the disposition of these elements and the axes in the brackets 'l1 for the doctor knife holder 44 is such as to create a trimmed edge parallel with the base line of the doctor knife holder 4d. It will also be noted that the disposition of these. elements is such as always to cause the trimmed wiping edge of the doctor knife 48 to be the same distance from the said opposite edge of the doctor knife holder 46 and the amount of the longitudinal projection of the doctor 48 from its holder d@ is thereby maintained constantly uniform. This dispositiornof these elements is to provide a uni form alignment'between the gauging edge of the holder 44 and the wiping edge of the doctor 61d. Such disposition of these alignments is utilized in the printing press where the doctor knife and its holder are mounted on aligned axes which in turn lare in constant alignment with the axis of the printing cylinder or respectively with the printing surface. In such manner a permanent alignment is obtained between the wiping edge and the printing surface and thereby the necessity of frequent readjustment of such alignments is eliminated.

I claim as my invention:

l. A machine for doctor knife maintenance comprising a support for a doctor knife holder, a table for supporting the doctor knife, and adjusting means associated with said table to adjust the position of said doctor knife with respect to said holder.

2. A machine for doctor knife maintenance comprising a support for the doctor knife holder, means associated with said support to locate said holder in a predetermined position, and adjusting means adapted to engage a doctor knife .endwise and to move said doctor knife with respect to the holder to adjust the distance of projection of said doctorlmife from said holder.

3. A machine for doctor knife maintenance comprising a support for a doctor knife holder,

nally of the holder for the removal of the worn wiping edge of a used doctor, said cutting means removing said edge in a single cut.

5. A machine for. doctor knife maintenance comprising a support for the doctor knife and its holder, adjusting means to adjust the longitudinal projection of said doctor knife with respect to its holder and means for reconditioning the worn wiping edge of a used doctor knife.

6. A machine for doctor knife maintenance comprising a support for the doctor knife and its holder, means on Said support to locate said holder in a fixed alignment thereon, and cutting` means for reconditioning the worn wiping edge of a used doctor, said cutting means being adapted to restore said wiping edge parallelism with said alignment of said holder.

7. A machine for doctor knife maintenance comprising a supportl for the doctor knife and its holder, means on said support to locate and maintain said holder in a fixed alignment thereon, adjusting means cooperating with said support to regulate the longitudinal `projection of said doctor beyond its holder, and cutting means for the restoration of the worn wiping edge of a used doctor, said cutting means being parallel with said alignment of said support to cause the restored wiping edge to be parallel with said comprising means for restoring the worn wiping edge of a used doctor, said means including a carriage, means to mount the carriage movably upon the machine, a pair of knives on the carriage, means to move the-carriage and means to actuate the knives While the carriage is moving to remove the worn edge with a single cut.

9. A machine for doctor knife maintenance comprising a pair of cutting discs capable of cutting away the worn wiping edge of a useddoctor knife, mechanical means to impart to said discs simultaneously both a rotating and longitudinal movement, the peripheral speed of said discs being in synchronism with the longitudinal surface speed thereof.

10. A machine for doctor knife maintenance comprising a pair of rotatable cutting discs being in cutting engagement and adapted to remove the worn wiping edge of a used doctork knife, means to impart to said discs, simultaneously Ipositive revolving and longitudinal movements being opposite'to the direction of their longitudinal movement.

11. A machine for doctor knife maintenance comprising a pair of rotatable cutting discs in cutting engagement and adapted to remove the worn wiping edge of a used doctor knife, means to impart 'to said discs, simultaneously positive revolving and longitudinal movements during the cutting operation, the direction of rotation of said discs at their engaging portions being opposite to the direction of their longitudinal-movement, the peripheral speed of said discs being in synchronism with the longitudinal surface speed thereof.

12. A machine for doctor knife maintenance comprising a frame, a carriage slidably supported on said frame, a pair of cutting discs rotatably supported on said carriage, said discs adapted to remove the worn wiping edge of a used doctor,

tate one of said gears, said gears being adapted to cause the rotation of said discs and a simul- Vtanecus longitudinal travel of said carriage.

13. A machine for doctor knife maintenance comprising va frame, a carriage slidably supported on said frame, a pair of cutting discs rotatably supported on said carriage, said discs adapted to remove the worn wiping edge of a used doctor, a train of meshing gears on the carriage in driving connection with the discs, and means to rotate one of said gears, means engaging one of the gears to cause the carriage to be moved upon motion of the gears, said gears being adapted to cause the. rotation of said discs and a simultaneous longitudinal travel of said carriage, the gears being further adapted to cause the peripheral speed of said discs on their cutting edges to coincide with the surface speed of said carriage.

14. A machine for doctor knife maintenance comprising a frame, ay carriage slidably supported on said frame, a pair of cutting discs rotatably supported on said carriage, said discs adapted to remove the worn wiping edge of a used doctor, a train of meshing gears on the carriage in driving connection with the discs, and means to rotate one of said gears, means engaging one of the gears to cause the carriage to be moved upon motion of the gears, s 4d gears being adapted to cause the rotation of s ld discs and a simultaneous longitudinal travel of said carriage, the gears being further Iadapted to cause the direction of rotation of said discs at their cuttingy position to be reverse to the direction of movement of said carriage.

15. A machine for doctor Vknife maintenance comprising a frame, a carriage slidably supported on said frame, a pair of cutting discs rotatably supported on said carriage, said discs adapted to remove the worn wiping edge of a used doctor, a train of meshing gears on the carriage in driving connection with the discs, and means to rotate one of said gears, means engaging one of the gears to cause the carriage to be moved upon motion of the gears, said gears being adapted to cause the rotation of said discs and a simultaneous longitudinal travel of said carriage, the gears being further adapted to cause the peripheral speed of said discs on their cutting edges to coincide with the surface speed of said carriage, and being further adapted to cause the direction of lrotation of said discs at their cutting position to be reverse to the direction of movement of said carriage. f

' 16. A machine for doctor knife maintenance comprising a station for adjusting the longitudinal projection of the doctor knife with respect to its holder, a cutting station for removing the worn wiping edge of a used doctor knife, a movable support for the doctor and its holder, and means to move said support to locate said doctor in said adjusting or in said cutting station.

17. A machine for doctor knife maintenance comprising a Station for adjusting the longitudinal projection of the doctor knife with respect to its holder, a cutting station for removing the Worn wiping edge of a used doctor knife, a movable support for the doctor and its holder and means to move said support to locate said doctor in said adjusting or in said cutting station, and means to lock said support in either of said positions.

-18.'A machine for doctor knife maintenance comprising a table, a support for the doctor knife and its holder, and means for moving the support in such manner that said doctor knife will become deflected from its normal plane when said doctor knife is resting on said table whereby the doctor knife will be maintained in a substantially rigid condition to permit the same to be conditioned.

19. A machine for doctor knife maintenance comprising a cutting mechanism for the removal of the worn wiping edge of a. used doctor knife, said mechanism including a pair of cutting discs in cutting engagement and means to impart to the discs a rotating and a simultaneous longitudinal movement during the cutting operation, a support for the doctor knife holder, a table for the support of said doctor knife during the cutting operation. and means to move the support in such relative manner as to cause the said doctor to be under a longitudinal cross tension when it comes to rest on said table.

20. A machine for doctor knife maintenance comprising a cutting mechanism for the removal of the worn wiping edge of a used doctor knife, said mechanism including a pair of cutting discs in cutting engagement and means to impart to the discs a rotating and a simultaneous longitudinal movement during the cutting operation, a 'support for the doctor knife holder, a table for the support of said doctor knife during the cutting operation, and means to move the]` support in such relative manner as to cause the said doctor to be under a longitudinal cross tension when it comes to rest on said table and to present the wiping edge of said doctor to be trimmed in an even level with the line of engagement of said cutting discs with said doctor corresponding with the point oi engagement of said discs.

21. A machine for doctor knife maintenance comprising a movable support for the doctor knife and its holder, a mounting station at which the doctor knife and its holder are secured in the lsupport, a conditioning station at which conditioning operations are performed upon the doctor knife, and means to move the support to position the holder in either of the two said stations.

22. A machine for doctor knife maintenance comprising a movable support for the doctor knife and its holder, a mounting station at which the doctor knife and its holder are secured in the support, a conditioning station at which conditioning operations are performed upon the doctor knife, an adjusting station at which the position of the doctor knife with respect to the holder is adjusted, and means to move the support to position the holder in either of the three said stations.

ADOLPH WEISS. 

